Art of distillation



Feb. 3, 1931. R. D. HUNNEMAN ETAL ART OF DISTILLATION Filed April 1, 1925 Q "I Q 0 lf3 Q4 t l2 fr 1u D n N m Q n! q. lll g a Z V) 8 Patented Feb. 3, 1931 UNITED STATES PATENT OFFICE ROGER D. HUNNEMAN, 0F CHICAGO, ILLINOIS, FRANCIS M. ROGERS, OF WHITING,

INDIANA, AND ROBERT E. WILSON, OF CHICAGO, ILLINOIS, ASSIGNORS TO STAND- .ARD OIL COMPANY, OF WHITING, INDIANA, A CORPORATION OF INDIANA ART OF DISTILLATION Application led April 1,

The present invention relates to improvements in the art of distilling-hydrocarbon oils, and more particularly to the continuous distillation of heavy residues, and Will be fully understood from the following description, illustrated by the accompanying drawings, in Which apparatus is diagrammatically shown, partly in section, in which the invention may be carried out.

The process of this invention is intended more particularly for the distillation of heavy oils and residue oils, for example, oils having a gravity of 17 to 19 A. P. I. such as that derived by the distillation of mid-continent crude to a 20% bottom with steam.

Referring more particularly to the drawing, the residue oil to be distilled in accordance With this process is drawn into the intake of a pump 5 through line 6, and is forced out through line 7 into the inlet pipe 8 of a coil 9 mounted in a suitable furnace setting 10, in which heat is applied. The oil is received by the pump preferably directly from the last still of a continuous battery of stills and will ordinarily be at a temperature of 670 to 710 Ff. Steam is forced into the inlet pipe 8 of coil 9 through the pipe 11 controlled by valve 12. The steam thus introduced is preferably at approximately the same temperature as the oil, although, if desired, it may be supplied at a lower temperature, the

additional heat required .being supplied Within the furnace setting 10. The proportion of steam added may suitably be between 2 and 10 pounds per gallon of distillate oil produced, and preferably 4 to 5 pounds. Within the setting 10 the mixture of steam and oil is at least retained at the temperature at which the oil is received from the continuous battery, or may suitably be raised to 700 to 760 F. From the coil 9, the mixture of steam, oil and vapors passes out through the equilibrium line 13 controlled by valve 14 into an enlarged chamber 15, in which a separation of unvaporized liquid from vapors takes place. Unvaporized liquid is discharged through the trapped tar line 16 and vapors, including vaporized oil and steam, through the vapor line 17, which is suitably protected by a baflie or shield 18 so that un- 1925. Serial No. 19,859.

vaporized liquid is not carried out with the vapors. Tar discharged through the line 16 is caused to pass through lines 19 controlled by valves 20 into either of receivers 21, as desired. The receivers 21 are provided with valved outlets 22 and suitable vents.

From the line 17 vapors pass into a cooling chamber 23, which is cooled by a suitable medium, such as Water, passing through the coil 24, to a temperature not sufficiently loW to condense the steam. Substantially all of the oil is condensed and discharged from the cooling chamber 23 through the line 25 rovided With a valve 26 into a receiver 27. apors, consisting almost entirely of steam,

are collected Within the cooling chamber 23 by the inverted hood 28 and pass out through the line 29 and trap or separator 30 through the line 31, by which the uncondensed steam is conducted to the condenser 32. Entrained condensate carried by the vapors passing through the pipe 29 is collected in the trap 30 and returned by line 33 controlled by valve 34 to the line 25 leading to the receiver 27. The vapors uncondensed in the chamber 23, and which consist substantially entirely of steam, are condensed in the condenser 32,

cooled by Water, brine or other suitable mediums and the resulting condensate passes through the valved line 38 into the receptaele 35.

Each of the receivers 21, 27 and 35 is connected to a vacuum line 36 leading to a suitable vacuum pump 37, by means of which a desired vacuum is maintained upon the entire system.

In operating, the vacuum pump is so controlled that the system, from control valve 14: on, operates under an absolute pressure of 25 to 75 millimeters of mercury, and preferably about 50 millimeters. The proportion of steam, as hereinbefore set forth, is adjusted to secure the desired proportion of distillate, the partial pressure of the oil in the system being 2 to 10 millimeters. A suitable temperature is maintained by the furnace in the setting 10 to secure this partial pressure. The oil is maintained, in the separating chamber for a very short period oftime, preferably not over 1 second for the vapors and not over 10 seconds for the liquid oils at the temperature required, which may be from 700 to 750 F. As the oil is drawn into the system at a temperature of 680 to 700 F., and the steam supplied is preferably preheated to about that temperature, it is readily apparent that but little heat is re uired to vaporize the desired part of the oi and to produce an equilibrium between vapors and liquids within the equilibrium pipe 13 and separating chamber 15.

As a result of this operation, from to 85% of the oil subjected to distillation may be secured as an overhead distillate; thus, if the initial material is a 20% residuum of midcontinent crude, an additional 16% of the original crude is secured as a distillate and the filial residuum amounts to only about 4% on the original crude. An 80% distillate on such an initial material, obtained by operating the process hereinbefore described, has the following characteristics:

22.6 A. P. I. gravity; flash 390 F.; 72 seconds Saybolt viscosity at 210 F.; solid at 90 F.

An additional characteristic of thisfdistillate is the fact that is contains petrolatum, about 9% of petrolatum being obtained from the distillate by reducing it to a 40 to 60% bottom and subjecting it to the ordinary naphtha settling process.

A residuum produced in accordance with this process was found to have a melting point of about 196 F., a gravity of 1.07 at 77 F., and a. flash point of 650 F. By air blowing, an asphaltic product is'obtained having a melting point in excess of 300 F. This residue showed 94 to 96% soluble in carbon tetrachloride, 96 to 98% soluble in carbon disulfide and 65 to 75% soluble in petroleum ether, thus showing that substantially no cracking had taken place in the process.

lt is readily apparent that the oil supplied to the system for distillation may be preheated in any suitable manner, instead of being drawn directly from a battery.

Although this invention has been described in connection with a particular procedure for carrying it into effect, it is not intended that the invention shall be limited to the specific details of the procedure set forth, except insofar as included .in the accompanying claims.

We claim:

1. The method of distilling heavy hydrocarbon oils comprising bringing oil to a temperature of 675 to 760 F. and supplying steam at a like temperature in the proportion of 3 to 10 pounds per gallon of final oil distillate, and securing equilibrium between such oil and steam while maintaining an absolute pressure not over millimeters, and subsequently separating unvaporized oil and vapors.

2. rllhe method of distilling a petrolatum containing oil to produce a petrolatum containing distillate comprising bringing the oil to a temperature not over 750 F. under an absolute pressure less than 75 millimeters in the presence of steam sufficient to eect distillation of a predetermined proportion of the oil with a partial pressure of 2 to 3' millimeters, and separating the resulting vapors from unvaporized liquid.

The method of distilling heavy hydrocarbon oils comprising bringing the oil to a temperature of 670 to 760 F. under an absolute pressure of 25 to 75 millimeters in the presence of steam in proportions to provide 4 to 5 pounds of steam per gallon of distillate oil.

4. The method of distilling heavy hydrocarbon oils which comprises bringing such oil to a temperature of 675 to 760 F., intimately mixing such oil with steam while maintaining an absolute pressure thereupon less than atmospheric but greater than the partial pressure of the oil, the proportion of steam being controlled to determine the proportion of oil evaporated, causing the intermingled steam and oil to traverse a Conduit in which the desired equilibrium is attained Without separation and introducing the steam and oil into an enlarged chamber in which separation of vapors from unvaporized oil takes place, the vapors being retained in said chamber for not over 1 second.

5. The method of distilling heavy hydrocarbon oils comprising bringing oil to a temperature of 675 to 760 F., continuously flowing such oil and steam at a like temperature through a confined passage to secure equilibrium therebetween without separation thereof, the steam being in the proportion of 3 to 10 pounds per gallon of final oil distillate, discharging the steam and oil mixture into an enlarged chamber and maintaining an absolute pressure in said confined passage and chamber of not over 75 millimeters.

6. The method of distilling residual hydrocarbon oils Without cracking which comprises heating such oil to 670 to 710 F., flowing the oil continuously through a. restricted passage accompanied by steam in the proportions of 2 to 10 lbs. per gallon of distillate oil produced, through a zone in which the mixture is subjected to heat to at least retain the temperature of the oil and to heat the mixture to not over 760 F., then passing the mixture to an unheated conduit at a velocity sufficient to prevent sepa-ration whereby thermal equilibrium of the mixture is secured and thereupon promptly separating the vapors and unvaporized portions of the mix ture, while maintaining in said conduit and during said separation an absolute pressure of not over 75 millimeters.

7. The method of distilling residual hydrocarbon oils without cracking which comprises admixing such oil with steam in the proportions of 2 to 10 lbs. of steam per gallon of distillate oil produced, bringing the mixture while in continuous flow to a temperature of 675 to 760, then passing the mixture in continuous flow through a restricted un'- heated passage whereby thermal equilibrium l.of the mixture is secured, and discharging chamber.

the' mixture from said passage into the vapor space of an enlarged chamber, whereby prompt sep-aration of the vapors and unvaporized liquid is effected, While maintaining in said passage and chamber an absolute pressure of not over millimeters.

8. The method of distilling heavy hydrocarbon oils comprising bringing the oil to a temperature of 670 to 7 60 F., intimately mixing such an oil With steam in proportion of 2 to l() lbs. per gallon of distillate produced, by passing it through an unheated conduit at a velocity sufficient to prevent separation, whereby thermal equilibrium of the mixture is secured, discharging the mixture from said passage into the vapor space of an enlarged chamber Within which the vapors are separated from the vaporized oil, the vapors being retained in said chamber for not over one second, While maintaining an absolute pressure of 25 to 75 millimeters inv said conduit and in said separating ROGER D. HUNNEMAN. FRANCIS M. ROGERS. ROBERT E. WILSON. 

